[meteorite-list] Antarctic Craters Reveal Strike

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Fri Aug 20 03:24:58 2004
Message-ID: <4125A6C6.31EF0B9D_at_bhil.com>

Hi, Everybody,

    Assuming that this first report is solid, is supported by followup
research, everybody agrees on everything, yada, yada, this has potentially
revolutionary, or at least upsetting, implications.
    Note the DATE of these huge impacts. Yes, boys and girls, it's almost
perfect match for the best estimated date of the Australasian tektite event.
So it would seem that decades of vain searching for a same-date impact
crater in Thailand, Cambodia, drilling in the Tonle Sap, et cetera, was a
big waste of time.
    Or are we going to insist that an invisible undiscovered crater in S.E.
Asia is responsible for the Australasian tektite event when we have a 200
mile crater in a field of craters in Antarctica at the right date? And right
next door, too.
    Let's say we accept the obvious conclusion that such a huge impact event
in Antarctica at the same time as the Australasian tektite event cannot be a
"coincidence," and move the Antarctic craters up to number one contender for
the cause of the Australasian tektite event.
    What does that do to the decades of theorizing, modeling, aerodynamic
studies, and generally self-reinforcing thought that explains the variations
in the tektites in the Australasian tektite strewn field (from Muong Nuong
to Australites) on the basis of their distance from a supposed S.E. Asian
impact when the impact is at the other end of the 10,000 mile long strewn
field?
    Shoots it all to hell, is what it does.
    Even worse, every theorist with a theory license agrees that the source
material for the formation of tektites is the surface rock of the Earth at
the point of impact. That's SURFACE rock, NOT sub-surface rock, the
Moldavites for example being explained by the composition of surface sand
layers, which gave them the properties that set them apart from other
tektites.
    OK, what's the surface rock of the Antarctic ICE sheet? Well, it's ice;
there isn't any surface rock. It's ICE. How do you make a tektite out of
ice? Beats me.
    The only source of rock is... the impactor itself. This, in turn, makes
things a hundred times worse, because everybody agrees that tektites cannot
be formed from any extraterrestial material that we know of: wrong elemental
composition, wrong isotopic composition, and so forth.
    In fact, the further one moseys down the logic trail from the obvious
and hard-to-escape acceptance of this immense crater field as the source of
the Australasian tektite strewn field, the worse it gets. It strongly
suggests that almost everything we think we know about tektites is wrong.
    Oh, no, how could that be? And us so smart and all...


Sterling K. Webb
-------------------------------------------------------------------------------------

    Of course, the first question is: how did they determine this date?
What's the +/- of the date? Is it the same for all the craters? More
details!
-------------------------------------------------------------------------------------

Ron Baalke wrote:

> http://news.bbc.co.uk/1/hi/sci/tech/3580230.stm
>
> Antarctic craters reveal strike
> BBC News
> August 19, 2004
>
> Scientists have mapped enormous impact craters hidden under the
> Antarctic ice sheet using satellite technology.
>
> The craters may have either come from an asteroid between 5 and 11km
> across that broke up in the atmosphere, a swarm of comets or comet
> fragments.
>
> The space impacts created multiple craters over an area of 2,092km (1300
> miles) by 3,862km (2,400 miles).
>
> The scientists told a conference this week that the impacts occurred
> roughly 780,000 years ago during an ice age.
>
> When the impacts hit, they would have melted through the ice and through
> the crust below.
>
> Professor Frans van der Hoeven, from Delft University in the
> Netherlands, told the International Geographical Union Congress in
> Glasgow that the biggest single strike seared a hole in the ice sheet
> roughly 322km (200 miles) by 322km.
>
> Impact melt
>
> This would have melted about 1% of the ice sheet, raising water levels
> worldwide by 60cm (2ft).
>
> The research suggests that an asteroid the size of the one blamed for
> killing off the dinosaurs 65 million years ago could have struck Earth
> relatively recently.
>
> Early humans would have been living in Africa and other parts of the Old
> World at the time of the strikes.
>
> But the impacts would have occurred during an ice age, so even tidal
> waves would have been weakened by the stabilising effect of icebergs on
> the ocean.
>
> The craters were resolved using satellite data to map gravity anomalies
> under the ice sheet.
Received on Fri 20 Aug 2004 03:22:46 AM PDT